An increasing number of vehicles have, in addition to an ordinary assistance function (assistance mode) that assists the steering ability of the driver, an automatic steering function (automatic steering mode) that does not require the driver to perform steering, as typified by parking assistance and lane-keeping traveling. In particular, the parking assistance plans a traveling path for the own vehicle so as to avoid the position of an obstacle and performs automatic steering such that the own vehicle follows the traveling path.
In the field of robotics, many findings have been obtained for a traveling path generation method. As one of generation methods that determine the attitude angle of a two-wheeled independently-driven mobile robot, there is a known method that executes feedback control, such that the mobile robot follows a target path, by using a group of specific functions based on information regarding the position and attitude angle of the mobile robot (see, for example, Non-Patent Document 1).
Also, many patent applications have been filed for a parking assistance apparatus for a four-wheel vehicle. For example, the following parking assistance apparatuses are known: a parking assistance apparatus that enables a vehicle to travel while turning the steering wheel so as to prevent a collision with an object in the surroundings (see Patent Document 1); and a parking assistance apparatus that generates a parking path based on an input from an obstacle detection sensor and, if the vehicle is moved along the parking path and comes close to an obstacle, calculates a distance to the obstacle and displays the calculated distance on a display portion (see Patent Document 2).